BIO 3330 Biomagnification Introductory Information

BIO 3330 Biomagnification Introductory Information

BIO 3330, Fall 2020

Lab #10 (20 points)

Biomagnification

Introductory Information:

Ever since the industrialization of the modern world, anthropogenic pollution has been a major issue affecting nearby ecosystems. Everything from oil spills to carbon emissions can mean devastation to the wildlife it comes in contact with. What is even worse, however, is when these chemicals remain in the ecosystem, or even inside the animals themselves, for extended periods of time. As animals eat other animals or plants, some of these toxins are absorbed into the predator and accumulate. This is what ecologists refer to as Biomagnification. Biomagnification is defined as the concentration of toxins in an organism as a result of its ingesting other plants or animals in which the toxins are more widely dispersed. A chemical infamously known to bioaccumulate is a pesticide called Dichlorodiphenyltrichloroethane, or DDT.

DDT is a pesticide that was put into widespread use after World War II. It is used mainly for agricultural pests, but also as a method of mosquito control. It wasn’t until Rachel Carson’s 1962 book Silent Spring that people started questioning the chemical and its environmental affects. It enters the ecosystem when some of the residual chemical remains on the plant material or it washes off the plant into the soil, eventually making its way to a body of water. The DDT that remains on the leaves of plants is ingested by primary consumers such as insects and rodents. DDT breaks down in the body of animals to become a chemical called DDE. DDE stores in the fatty tissues of animals and tends to stay in the body. At high concentrations, it can result in nervous system damage, immune system problems, thyroid problems, eggshell thinning in some birds and death. The slow decline of several kinds of birds of prey in the US largely reflects the effect of eggshell thinning caused by DDE bioaccumulation in female birds. Thin eggshells tend to break before embryos can fully develop and hatch. Now that the devastating effects of DDT are being realized, many countries have banned the use of it. However, it is still used as mosquito control in some countries where mosquitoes carry deadly illnesses such as malaria. Silent Spring is credited for helping to start the 1960’s environmental movement that led to the creation of the Environmental Protection Agency.

Objectives:

To introduce the concept of biomagnification and the effects it has on an ecosystem. To understand the connection between food webs and biomagnification of toxic chemicals. Explain the effects that biomagnification can have on the economy and human health.

Materials:

100 slips of paper: “phytoplankton”

20 small cups: “zooplankton”

5 medium cups: “minnow”

2 large cups: “eel 1 and 2”

1 bowl: “osprey”

2. Two eels then come along for dinner. One eel eats 2 minnows and the other eel eats 3 minnows. Move the correct number of slips from the minnow cups into the eel cups. Write the amount of DDT ingested by each eel onto the pictures below. Use the instructions from step 1 to calculate the total amount of DDT for each.

Eel #1

17.5

Eel #2

28.85

4. Finally, an osprey flies by and eats both eels. Move the correct number of slips from the eel cups into the osprey bowl. Calculate and then write the total amount of DDT ingested by the osprey onto the picture below:

57.34

At 0.00002, 0.00004, and 0.0001 ppm of DDT, after 1000 ticks, report the mean current DDT contamination of the different organisms (7 pts).

1. What is the difference between bioaccumulation and biomagnification? (3 pts)
2. Define tertiary consumers in your own words, give an example of one and describe why this species may be more susceptible to biomagnification? (5 pts)
3. With biomagnification in mind, what foods should humans limit their consumption and what are the dangers if they do not? (5 pts)

PLACE THE ORDER WITH US TODAY AND GET A PERFECT SCORE!!!